CVE-2023-32675

LOW3.7EPSS 0.25%

Vyper's nonpayable default functions are sometimes payable

Published: 5/22/2023Modified: 2/22/2026

Description

### Impact in contracts with at least one regular nonpayable function, due to the callvalue check being inside of the selector section, it is possible to send funds to the default function by using less than 4 bytes of calldata, even if the default function is marked `nonpayable`. this applies to contracts compiled with vyper<=0.3.7. ```vyper # @version 0.3.7 # implicitly nonpayable @external def foo() -> uint256: return 1 # implicitly nonpayable @external def __default__(): # could receive ether here pass ``` ### Patches this was fixed by the removal of the global calldatasize check in https://github.com/vyperlang/vyper/commit/02339dfda0f3caabad142060d511d10bfe93c520. ### Workarounds don't use nonpayable default functions

Affected packages (2)

  • PyPI/vyperfrom 0, < 0.3.8
  • PyPI/vyperfrom 0, < 02339dfda0f3caabad142060d511d10bfe93c520. | from 0, < 0.3.8

CVSS scores

SourceVersionSeverityVector
osvCVSS 4.0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
osvCVSS 3.1LOW3.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

References (7)